Dave’s RV-7A Building Log

I started making some new brackets for the vents. The ones from Experimental Air kind of sort of fit, but I decided I’d just rather have ones that really fit well. I used .040 instead of the .063 that seemed like overkill. I cut them, made the bends, and laid out the holes for the side skins.

Since I had the vise unburied for bending the brackets, I decided to work on the throttle quadrant clevis ends a bit. I picked up a perfect Dremel bit for the job from Lowes, a 1/8″ tungsten carbide cutter. I worked perfectly on the clevis ends and allowed the cable to follow a much better angle. Might take a tiny bit more grinding, but they’re nearly perfect. The grinding didn’t significantly impact the strength of the clevis ends at all. I supposed if they were holding 1000 pounds of load, I’d worry about it. This is a very low-load application. The picture shows the difference in angle I was able to achieve after grinding the clevis end.

Messed around with the throttle quadrant a little bit. I discovered right off that the throttle lever was backward. The hole for the cable attachment is closer to one side than the other. The way the lever was installed, I couldn’t get the clevis end on it at all. I disassembled almost the entire thing just to get the lever turned around, but it was a good opportunity to figure out how it’s built. It really is a nice unit.

The other major problem is that there isn’t enough clearance between the clevis and the lever arms. You can see in this picture that the cables have to exit at nearly a 45 degree angle. That isn’t going to work. I’ve seen one builder file away part of the lever. I’m going to try filing the clevis end a bit.

I also measured the throw of the levers versus the throw needed. The throttle and mixture seem right on, but the prop pitch needs to be reduced. I’ll have to drill another hole, but that’s a good thing because right now the clevis pins would interfere with each other.

A couple of deliveries showed up today. The custom quadrant cables arrived after 6 weeks. They said it would take 4-6 weeks, but I’m usually optimistic. It looks like they’ll work great. One minor issue is that the diameter of the cable is .25″ and the firewall eyeballs that I have are .26″. I’ll just wrap some electrical tape around them or something. It won’t take much.

The LED position light kits also arrived from CreativAir. These look great. I could have gotten them pre-assembled, but I enjoy soldering. Used to build Heathkits when I was a kid.

It was tough to set aside those two fun items to work on the cabin vents. Classic Aero Designs should be starting my interior soon, and they need some dimensions. In order to do that, I need the cabin vent brackets in place. I received these brackets from Experimental Air, and I’m not impressed by them. They were not pre-bent, and from experience I know that trying to bend something to fit a specific dimension is very difficult. I gave it a shot, but they did not turn out well. The holes for securing them to the side didn’t line up with the pre-punched holes and the bend is 1/32″ short of where it needs to be. The brackets would pull in the side skins creating a pucker on the outside of the plane without some sort of shim. They also are not made from Alclad and needed some trimming so they wouldn’t interfere with the panel bottom flange.

It looks pretty good in this picture, but it really isn’t fitting well. I’m going to just make my own out of some spare sheet. To summarize, the vents are great, the brackets are junk.

This is the template that Classic Aero Designs sent. It’s printed on posterboard, and gets cut to fit around the vent bracket. Many people use a custom vent, since the one that Vans supplies is pretty junky. And even the standard one can vary in location. This template tells them where to cut around the vent.

They also wanted a picture of any custom locations for the ELT, fire extinguisher, etc. I’m planning on putting the headset jacks in the F-705 bulkhead, so I made a little tag and took a picture of it for them. I’m not sure if this spot is covered by their standard interior panels or not.

Deburred the panel reinforcement angle. I also removed the blue plastic and deburred most of the panel openings as well. It was actually pretty easy to clean up after the water-jet cutting process. I also noticed that the cut out for the avionics stack was almost too low. There’s a tiny bit of the hole for the canopy release still visible at the top.

I spent a little time trying to figure out where to put the re-located panel rib. I’d like to put it outboard (left) of the EFIS. I think the avionics stack will stabilize the middle of the panel just fine. However, on the left I have switches and then there’s the canopy to worry about. I might have to modify the rib somewhat to make it fit there.

On the right side, I’m hoping I can leave the rib in the stock location, but just alter the rib a bit to fit around the co-pilot screen. The stock location of the panel ribs really couldn’t be any worse. It’s right in the middle of any sort of large-screen EFIS or engine monitor.

I riveted on the panel attach angles. It’s pretty tricky to get a bucking bar inside the forward canopy deck. I messed up one rivet with a stair-step shop head and had to re-do it. Of course I had to install the panel and try out the supports. Looking very cool.

Adele had a swim meet, so I got home kind of late. I spent just a little time drilling the panel reinforcement angle. It’s looking good. Now I just need to decide how I’m going to paint the panel.

The band saw blades finally showed up from Lowes online. It was truly incredible how much better the new blade cut. I used it to clean up the relief cuts I made earlier in the panel reinforcement angle. From there it was a lot of filing and sanding to get everything smooth. I was going to start drilling the panel to the angle, but it was nearly 90 in the garage and I wasn’t sure I was thinking completely straight. Better to wait and get it absolutely right tomorrow.

The hatch covers turned out great. Epoxy is such a cool material, when it works right. They just need a little drilling and countersinking and nut plating.

I went down to Lowes at lunch time to pick up some band saw blades, and of course they’re out of them. And nobody was in sight to ask about them. I ordered the blades from their web site instead. It almost took longer to get through their terrible online store than driving down to the store 5 miles away.

Since I couldn’t work on the panel reinforcement angle, I started working on the panel attach points at the canopy deck. I should have done these a long time ago, especially before I cut the left panel rib. I had to do a lot of measuring left vs. right to make sure I had the panel in the right place. At least I already had the angles made. After probably 30 minutes of measuring, and re-measuring, and re-measuring, I drilled the angles to the canopy deck and the panel to the angles. I drilled some of the angles for nut plates, but that’s about where I ended for the day.

I’m also starting to work on the electrical planning some more. I pulled out the diagrams I sketched out several months ago. Now that I have more of the components, I can finalize wire sizing and runs.

Working on the panel is a lot more fun than tweaking the cowl. I’m getting re-inspired about getting the plane into the air. I’ve had some serious ups and downs in enthusiasm on this project. It’s no surprise that many people never finish their kits.

EAA 1440 meeeting last night. Charlie Cotton, a DAR, covered registering a home-built. Very timely and informative.

I had to run to the store to pick up some more Solo cups for mixing epoxy. I found some short, wide cups that work great. I mixed up a batch of structural filler and used that between the two parts of the forward hatches. I think those things are going to work pretty well.

I let that set up and worked on the reinforcement angle for the panel some more. I drilled all the holes in the angle and then marked some lines for cutting on the band saw. Unfortunately, I’ve used the band saw for cutting fiberglass. It’s amazing how fiberglass instantly dulls any cutting tool. I struggled through the cuts, but they don’t look good. It’s going to take a lot of filing. I’m going to pick up a new blade and see if I can clean up the cuts.

Much to my surprise, the panel arrived. I thought for sure it was going to take a few more phone calls to get it moving through the process. The panel looks good overall. I checked out the fit of several things. A few openings need to be enlarged slightly, but the edges need to be deburred anyway. The water jet cutting definitely leaves a rough edge. (Edit 7/7/06: The edge was kind of like a rough sandpaper. With a little deburring and sanding, it cleaned up quite easily.)

I also ordered air vents from Experimental Air, and those arrived as well. They look and operate very nicely. The brackets aren’t pre-bent, so I’ll have to do a little work there. It also looks like I’ll have to trim the panel a tiny bit in order for the vents to fit in correctly into the corners.

The 3 2-1/4″ holes below the EFIS are really close together. I verified that the airspeed and altimeter should fit on either side of the Digitrak just fine. The only problem is the Nulites. They are much wider than the instruments. The instructions say they can be cut down, so I’ll have to do that along one edge.

I did various messing around with the panel, checking the fit and finish. I then pulled out some 3/4 x 3/4 x .063 angle and marked it up to make the reinforcement for the top edge. I don’t have enough spare angle to make another, so hopefully I don’t screw it up.

I didn’t get anything done on the project last night as we had another Seattle Eastside EAA chapter meeting. It’s fun being on the ground floor of forming a new group. Everybody seems to be enjoying it so far.

I’ve been going back and forth with Ross at Experimental Air a few times on the panel. He’s doing a fantastic job of laying out the parts. This is what we have so far:

I’ll need him to tweak the switches just a tiny bit more in order to have a spot to attach the throttle quadrant mount. Other than that, it’s looking pretty darn near done.

The two large screens are a Dynon EFIS-D100 on the left and EMS-D120 on the right.